1. Field of the Invention
The present invention relates to an imaging device, an imaging method, and an image processing program and particularly to an imaging device, an imaging method, and an image processing program that can acquire a plurality of images having different properties at the same time.
2. Description of the Related Art
An imaging device that includes a multiple-property lens and a directional sensor is suggested in the related art (JP2012-253670A and WO2012/043212A). The multiple-property lens includes a first area having a first property and a second area having a second property that is different from the first property. The directional sensor receives a luminous flux passing the first area of the multiple-property lens and a luminous flux passing the second area by pupil division and can acquire a first image having the first property and a second image having the second property at the same time.
The directional sensor is configured to have an angular property with respect to light detection sensitivity, and the following directional sensors are disclosed in JP2012-253670A and WO2012/043212A.
(1) A directional sensor that is caused to have an angular property with respect to light detection sensitivity for each light receiving cell by allocating one microlens to a plurality of light receiving cells.
(2) A directional sensor that is caused to have an angular property with respect to light detection sensitivity by arranging a light shielding mask near a light receiving cell and shielding a luminous flux passing a first area of a multiple-property lens or a luminous flux passing a second area of the multiple-property lens.
(3) A directional sensor that is caused to have an angular property with respect to light detection sensitivity by a prism element by disposing, for each light receiving cell, the prism element functioning as a prism.
The imaging devices disclosed in JP2012-253670A and WO2012/043212A can image various images having different properties at the same time with the single directional sensor and the multiple-property lens by combining the multiple-property lens having different properties according to a location in a pupil area and the directional sensor having an angular property with respect to light detection sensitivity.
Also suggested is an imaging device that can image various images having different properties at the same time by using a directional sensor in which a light shielding mask is disposed in only a part of light receiving cells (WO2013/027507A).
The imaging device disclosed in WO2013/027507A includes a multiple-property lens and a directional sensor. In the multiple-property lens, a proportion a occupied by a first area of the multiple-property lens is different from a proportion b occupied by a second area of the multiple-property lens (a<b). The directional sensor includes a first light receiving cell in which a light shielding mask is disposed to cause only a luminous flux passing the first area of the multiple-property lens to be incident, and a second light receiving cell on which luminous fluxes passing the first area and the second area of the multiple-property lens are incident. A first image having the property of the first area is acquired from the first light receiving cell of the directional sensor, and a second image having first and second properties is acquired from the second light receiving cell. While the first property and the second property of the multiple-property lens are mixed in the second image, the second image mainly has the second property since the proportion b occupied by the second area is greater than the proportion a occupied by the first area.
While the directional sensors disclosed in JP2012-253670A and WO2012/043212A are configured to have an angular property with respect to light detection sensitivity, it is difficult to perform accurate pupil division of a luminous flux passing the first area of the multiple-property lens and a luminous flux passing the second area of the multiple-property lens, to cause the luminous flux passing the first area to be incident on only the first light receiving cell, and to cause the luminous flux passing the second area to be incident on only the second light receiving cell. The first image includes a crosstalk component that indicates the property of the second area of the multiple-property lens, and the second image includes a crosstalk component that indicates the property of the first area. The second light receiving cell of the directional sensor disclosed in WO2013/027507A does not have an angular property with respect to light detection sensitivity. Thus, the second image acquired from the second light receiving cell includes a crosstalk component that indicates the first property of the multiple-property lens.
In WO2013/146506A, disclosed is a method for removing or reducing a crosstalk component from each of a first image and a second image by image processing. In JP2005-286104A, disclosed is a color solid-state imaging device that has different light reception areas of a first light receiving cell and a second light receiving cell (light receiving section) arranged in panes (checker pattern).